What condition is likely to contribute to a potential voltage collapse in a power system?

The condition that is likely to contribute to a potential voltage collapse in a power system is insufficient dynamic reactive resources. Dynamic reactive resources, such as synchronous condensers and flexible AC transmission systems (FACTS), provide the necessary reactive power support that helps maintain voltage levels during fluctuating load conditions and disturbances.

When reactive power is inadequate, particularly during times of heavy loading or sudden changes in demand, the system may experience voltage instability. Insufficient dynamic reactive resources can lead to higher voltage drops across transmission pathways, which can eventually result in low voltage conditions or even a voltage collapse if corrective measures are not taken.

In contrast, while overloaded generation units can impact reliability, they primarily lead to frequency issues rather than directly causing voltage collapse. High system frequency can indicate generation exceeding load but does not specifically contribute to voltage collapse. Excessive load demand may increase the risk of voltage drop, but it is the lack of responsive reactive resources that directly causes the system's inability to maintain adequate voltage levels under stress. Therefore, the emphasis on insufficient dynamic reactive resources precisely highlights the critical role these components play in voltage stability within the power grid.